Approximately 85 million gallons of high-level waste (HLW) is currently stored in underground tanks at the Hanford Reservation and the Savannah River Site (SRS). The waste consists of a hydroxide-rich precipitate (sludge) and a sodium-rich supernate. The supernate is a NaOH rich solution containing lesser amounts of NaNO3 and NaNO2 and small amounts of soluble fission products, cladding materials, and organics (volatile organics and semi-volatile organics known as VOCs and SVOCs).The Department of Energy (DOE) has chosen glass as its waste form for both sludge and sodium-rich supernate. However, because of the volume of the supernate, alternatives to vitrification are being sought for some of this waste. One alternative is to remove 137Cs and 90Sr from the supernate. Decontaminating the waste in this way allows the waste to be designated as low-activity waste (LAW) and as such the waste now becomes eligible for solidification and disposal on site. SRS is solidifying its LAW with a blended Portland cement forming Saltstone. Hanford has been considering a bulk vitrification process in which the LAW will be mixed with Hanford soil and vitrified in place in a disposable carbon-arc powered glass melter/waste container. Both waste forms can then be buried on site in appropriate vaults or low-level waste land fills. A hydroceramic is an alternative waste form designed to solidify and stabilize LAW that is made from metakaolin plus NaOH and/or NaOH rich LAW supernate. In addition to NaOH, LAW can contain a wide range of sodium nitrate and sodium nitrite concentrations.Although a hydroceramic waste form can be made directly from some types of decontaminated waste, e.g., those that are highly alkaline (8--12M NaOH) and contain less than 25 mol% of NOx (NOx is used as the short-note for nitrates and nitrites in this article.) relative to the total Na in the waste, by simply mixing the LAW with metakaolin and curing the resulting paste at 90°C, the remaining LAW,… [ABSTRACT FROM AUTHOR]